Known prior art safety belt buckle constructions are disclosed in the following U.S. Pat. Nos. 3,131,451; 3,237,258; 3,242,546; 3,274,655; 3,277,548; 3,449,800; 3,465,393; 3,483,599; 3,588,969; 3,623,191; 3,639,951; 3,686,720; 3,716,895; 4,015,094; 4,052,775; 4,060,879; 4,064,603. The closest known prior art construction is disclosed in U.S. Pat. No. 3,588,969.
Some of the problems in prior art constructions which the present invention is directed to overcome include the following:
a. high release efforts under 150 pound loop load generally very close to 30 pound maximum government mandated release pressure; PA1 b. high insertion efforts due to high output spring under latch; PA1 c. high cost and low reliability of making "J" shape in front of buckle for lever retention and reaction; PA1 d. high cost of fabrication and assembly due to number of component parts involved. PA1 a. a front lead in cooperating with the frame for easy tongue insertion; PA1 b. an area which supports the tongue for positive latch stripping when the push button is depressed for releasing the buckle; PA1 c. columns for push button spring reaction force to maintain the lever with correct preload bias; PA1 d. provide material around the webbing slot of the frame to distribute loading of the webbing and eliminate "cutting"; PA1 e. provide an area for housing electrical switch components; PA1 f. keeps lever located in assembly.